NEW YORK {AP} A scientist at New York's Rockefeller University won the Nobel Prize in medicine Monday for discovering how proteins find their rightful places in cells a process that goes awry in diseases like cystic fibrosis and plays a key role in the manufacture of some medicines.

Dr. Guenter Blobel, 63, a German native who became a U.S. citizen in the 1980s, said that by showing how cells work when they're healthy, his research might help scientists understand what goes wrong in diseases.

"It's not a cure for AIDS, it is not a cure for Alzheimer's it is basic cellular research," Blobel said after the $960,000 prize was announced in Sweden.

Blobel, who moved to the United States in the 1960s, received the prize for discoveries that began in the early 1970s at Rockefeller.

A typical cell in a mammal contains a billion or so chain-like proteins. Some are building blocks for cell structures, and others encourage specific chemical reactions. Blobel essentially found that after proteins are created, they reach their various workplaces because they carry signals, somewhat like ZIP codes, that indicate where to go.

These signals determine whether a protein ends up in a certain compartment of a cell, takes up residence in the cell wall, or is expelled from the cell. Mistakes can kill a cell or cause disease, and Blobel's work has helped explain the molecular basis of several genetic diseases.

Cystic fibrosis, for example, appears when a certain protein doesn't take up its post in the cell wall. Some forms of inherited high cholesterol and a condition that causes kidney stones at an early age also involve mistakes in routing.

Scientists have taken advantage of the routing process in biotechnology labs, where they can make vats of cells pump out medicinal proteins such as growth hormone. Those proteins must be secreted from the cells, a process controlled by routing signals, before they are recovered.

Danny Schnell of Rutgers University, who studies movements of proteins within cells, said Blobel's idea about the protein ZIP codes was a fundamental contribution.

"The rest of us have come along and essentially filled in the details and have contributed to understanding the basic mechanisms, but that fundamental hypothesis really has stood the test of time as a basic principle of biology," Schnell said.